Add basic support for the Blackfin architecture

For uClibc, the name of the Blackfin architecture is 'bfin'. Actually,
the naming of the architecture is quite messy: for toolchain tuples
and uClibc, it's bfin, but for the kernel, it's blackfin. We've
arbitraly choosen to name it "blackfin" in Crosstool-NG.

Add Blackfin-related uClibc patch to fix a build failure related to
fork() being used in unistd/daemon.c.

Yann E. MORIN:
Apply the patch to the kernel/linux build script to use 'linux'
in the noMMU tuples. See:
http://sourceware.org/ml/crossgcc/2010-04/msg00010.html

 Original patch from Gentoo.

 -= BEGIN original header =-

 -= END original header =-

 diff -durN uClibc-0.9.30.orig/libc/inet/resolv.c uClibc-0.9.30/libc/inet/resolv.c

 --- uClibc-0.9.30.orig/libc/inet/resolv.c	2008-11-02 01:25:33.000000000 +0100

 +++ uClibc-0.9.30/libc/inet/resolv.c	2009-02-07 09:57:59.000000000 +0100

 @@ -1788,7 +1788,7 @@

  int gethostent_r(struct hostent *result_buf, char *buf, size_t buflen,

  	struct hostent **result, int *h_errnop)

  {

 -	int ret;

 +	int ret = HOST_NOT_FOUND;

  	__UCLIBC_MUTEX_LOCK(mylock);

  	if (__gethostent_fp == NULL) {